Artificial tooth-crown and process of making same.



No. 693,884. Patntod Feb. 25, I902.

v E. NAGY. ARTIFICIAL TOOTH CROWN AND PBOOESS OF MAKING SAME-(Application 8106. ha. 16, 1901.)

(No Model.)

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, latter or by means of dentists cement.

UNITED STATES I PATENT OFFICE.

EMIL NAGY, OF BUDAPEST, AUSTRIA-HUNGARY.

ARTIFICIAL TOOTH-CROWN AND PROCESS OF MAKING SAME.

SPECIFICATION forming part of Letters Patent No. 693,884, dated February25, 1902.

Application filed January 16, 1901 Serial No. 43,449- (No model.)

To all whom it may concern: I

Be it known that I, EMIL NAGY, a subject of the Emperor ofAustria-Hungary, residing at IV. Varoshaz utcza 12, Budapest, Austria-Hungary, have invented certain new and useful Improvements in ArtificialTooth-Crowns and Processes Employed in Makingthe Same, of which thefollowing is a specification.

The object of this invention is to provide a novel artificialtooth-crown which possesses important advantages over formertoothcrowns.

In the pivot or pin-connected teeth at present in general use a pin isemployed which is set into the crown either in the firing of the In suchcases the crown has to be ground accurately to fit thepreviouslyprepared root, which is a most tedious operation. In the caseof very deep roots an accurate fit is nearly impossible, in which caseit is necessary to resort to some other equally tedious process. It isespecially important to observe that in these former crowns the fittingof the pin in its proper position is usually most difficult,whicli isnot the case with the crown of my invention.

The process of my invention besides being quite simple also results in amore accuratelyfitting and durable crown.

In the accompanying drawings, illustrating embodiments of my invention,Figure 1 is a side view of a front lower tooth provided with my improvedcrown. Fig. 2 is a longitudinal section of Fig. 1. Fig. 3 is across-section on the line A B of Fig. 2. Figs. 4 to 8 illustrate variousforms of cramps which may be employed in connection with my improvedcrown. Fig. 9 is a side view of a back tooth provided with a modifiedform of crown especially adapted for back teeth. Fig. 10 is alongitudinal section of Fig. 9. Fig. 11 is a cross-section on the line CD of Fig. 10. Fig. 12 is a cross-section on the line E F of Fig. 9. Fig.13 is a section on the line G H of Fig. 11. Figs. 14. to 17 illustratevarious forms of cramps. Figs. 18 and 19 illustrate a connecting-pin inelevation and cross-section, respectively; and Fig. 20 illustrates theimproved crown connected with a hollow pin.

In practicing my improved process the crown is fitted to the exposed endof the root by molding on the preferably porcelain body of the crown abase made of any suitable material and whose lower face is molded to fitthe end of the root. For the ordinary pin connection the pin is embeddedin said base, preferably by casting the base about the pin, while thelatter is held in such a position that it will enter the cavity of theroot. The molding of the base is most conveniently effected by fittingthe body of the crown at its front edge to the front edge of the root.The rear portion of the body is shorter than the front,

so as to leave a space at the rear between the body and the root. Thebase is preferably secured strongly to the body of the crown by means ofcramps inserted into the body in any convenient way and projectingtherefrom, so

as to engage the base when the latter is molded on the crown. In thepreferred construction a pair of cramps is used, and the portion of thepin within the base lies between such cramps and is secured thereto bythe material of the base. Also I preferably use a hollow pin having afiat'head and cramps of different types for front and back teeth.

'As indicated in the drawings, the preferred form of my new crown islonger at the front than at the rear. In the crown-body 1 and projectingfrom the under side thereof are two cramps 3, Figs. 2 and 3, on oppositesides of the center line. For the six front teeth the construction shownin Figs. 2 and 3 is preferred, using pairs of substantially T-shapedcramps 3 3 3 3 3 3 or the like made of any suitable material, such asplatinum, and attached in any suitable way. With porcelain crowns thecramps are burned in-that is, inserted while the clay is soft, so thatthe firing of the clay fastens them in place perma- 9o nently. The endsof the cramps are prefer-' ably embedded in the crown-that is, do notproject through'to the outer face of the crown.

By this construction they are held very firmly and without longitudinallooseness in the 5 crown. For the teeth which are farther back, asindicated in Figs. 10 to 13, the employment of the'above-describedcramps would weaken the crown, since the shanks of such cramps wouldhave to be let into the crown at the Ioo point where the wall of thelatter is weakest. To prevent this, I prefer to use pairs of cramps 8 88 8 8 or the like, which project in the form of an arch or handle fromthe crown and are let into the stronger front and rear portions of thecrown at the ends of said cramps. The upper end of the pin 4 ispreferably fiattened and projects between the two cramps, its other endlying in the direction to enter the cavity of the root, as shown inFigs. 2 and 10. It is preferred to makethe pin 4 as a capillary tubewith strong walls. The base of the crown, which forms the connectingmaterial between the crown and the root, may consist of aneasily-fusible metal, such as lightning-cast or the like, which is madeto completely fill the free space between the crown and the root by amolding process, as hereinafter explained, which fits accurately theroot as well as the crown and which at the same time provides a stiffconnection between the cramps and the pin.

Obviously the cramps for the six front teeth need not be exactlyT-shaped, but may be of any of the other forms shown in Figs. 4 to 8 orof any form similar to these and of any suitable cross-section. Thecramps for the back teeth may likewise be of any suitable form andcross-section. Figs. 14 to 17 show modifications of the arched orhandle-shaped design.

As above explained, there is employed with my improved tooth-crown pin4, Figs. 18 and 19, having a body of any desired shape in cross-sectionand preferably flattened at its upper end, which projects between thecramps, and sharpened or pointed at the end which is to project into theroot. The surface of the pin is roughened, as by the grooves shown, inorder to hold it more firmly in the cement. I prefer also to provide apassage 7 in the pin 4, which facilitates the removal of the pin in caseof the breakage of a crown which has been set in position and hardenedin the manner hereinafter described. By reason of the capillary passagea drill can be inserted very easily, and by the employment ofasufficiently strong drill the whole pin can be removed withoutdifficulty. My improved hollow pin is thus a great improvement over thesolid pins formerly in general use.

A detailed description of the preferred process of mounting my newtooth-crown is as follows; The tooth-root 9: is prepared in a sort offunnel shape, as shown most clearly in Figs. 2 and 10. A suitablecrown-body for the same is then selected, and the thin front portion 5thereof is ground to fit the root accurately. A pin 4 is now insertedinto the cavity of the root in such a position that the head thereofwill lie between the two cramps 3 or 8, Fig. 3 or Fig. 11, withoutaltering the position of the crown-body on the front edge of the root.Some softened wax is now placed on the crown-body about the cramps andthe pin, which, for the purpose of making a better connection, is coatedon its flat ends with easily-fusible metal, such as lightning-cast orthe like, and slightly warmed, is inserted between the cramps. Thepointed end of the pin is then stuck into the hollow ofthe root,together with a quantity of wax, and the crown-body is broughtaccurately to its proper position and connection. There is thus obtaineda full and true wax impression of the upper surface of the root. Thecrown-body, together with the wax and the pin, is then removed,carebeing taken not to distort the wax, and they are embedded in asoftplaster mold. The wax is then removed, as by means of hot water, and themold dried and filled with lightning-cast or the like, which forms abase for the crown, as explained. After the cooling of the cast the moldis broken, the crown, consisting of the porcelain body, molded base, andprojecting pin, is taken out, and the overflowed lightning-cast filedoff, so as to obtain an accurate impression of the edge of the root. Thecrownis now ready forsetting and is fastened to the root by means of asmall quantity of cement- G.

The described tooth crowns are easily mounted and require but littlegrinding. They are especially useful on account of the ease with whichthey may be joined to the root regardless of the direction of the hollowof the root. They are also easily fitted, even in the case of bad deeproots. Since they are made from an exact impression of the root, theyfit accurately, whereby the pressure in use is equally distributedoverthe inside of the root and the springing of the same is prevented.Furthermore, Very little cement or the like is used, whereby renewedulceration of the root is prevented. The setting of my improved toothcrown is as easy as possible, because being made from an accurate moldit naturally seeks its proper position on the root when it is set inplace and the pin is already in position to enter the cavity of theroot.

My improved tooth-crown is also capable of advantageous and labor-savingemployment in bridgework and metal plates. In any case I may employlightning-cast, caoutchouc, enamel, or any similar material as a binder.

In cases in which the natural cavity in the root does not run obliquelyor crookedly the improved crown may be used as a complete article ofmanufacture in combination with the hollow pin above described, as ahollowpin tooth, Fig. 20, the indirect burned connection of the pin tothe crown by the intermediation of the molded base and the burned-incramps being changed to a direct burned connection of the pin to thecrown, the head of the pin being substituted for the cramp as aconnecting member between the crown and the pin. The setting of thecrown takes place in this case with the help of a wax mold and the useof a fusible metal base in the manner previously described.

Obviously any number of cramps, one or more, may be used, though Iprefer a pair, for the reasons explained.

What I claim, and desire to secure by Letters Patent, are thefollowing-defined novel features and combinations,each substantially asdescribed:

1. The combination with an artificial toothcrown body of a pair ofcramps projecting from the under side thereof, and a pin hav ing itshead lying between said cramps and secured thereto.

2. An artificial tooth-crown comprising in combination a body, a base onsaid body molded to fit the exposed end of the root, and to bear equallythereon at all points, and a pin projecting from said base in adirection to enter the cavity of the root.

3. The combination with an artificial toothcrown body of a base on saidbody molded to fit the exposed end of the root, cramps projecting fromsaid body into said base and a pin projecting from said base in adirection to enter the cavity of the root," the head of said pin lyingbetween two of the said cramps and being secured thereto by said moldedbase.

4. In mounting tooth-crowns, the process which consists in fitting thebody of the crown to the front edge of the root, leaving a space at therear between said body and root, inserting a pair of cramps in saidbody, molding a base on said body to fit the rear portion 1 of theexposed end of the root, and embeddinga pin in said cast-base inadirection to enter the cavity of the root.

5. In mounting tooth-crowns, the process which consists in molding abase on the body of the crown to fit the exposed end of the root, andembedding a pin in said base in a at the rear between said body androot, and molding a base on said body to fit the rear portion of theexposed end of the root.

7. In mounting tooth-crowns, the process which consists in inserting apair of cramps in the body of the crown, molding a base bn said body tofit the exposed end of the root, and embedding a pin in said cast basein a direction to enter the cavity of the root.

In witness whereof I have hereunto signed my name in the presence of twosubscribing witnesses.

EMIL NAGY.

Witnesses:

BERNAUER ZIGMOND, FRANK DYER CHESTER.

